Marrow

See here.

The linked posts quote Manse Everard and Dominic Flandry on why reality does not conform to textbooks. Thus, Everard and Flandry agree with van Rijn quoted here. In particular, both Everard and van Rijn refer to knowing in the marrow.

(What I am doing here, partly, is just experimenting with linking to earlier posts because my linking facility has become iffy.)

Everard and the Technic History guys inhabit different versions of reality but both realities incorporate human history and much experience is common to both.